Dave:
A great video -- kudos to you and Bob! You guys did miss presentation of the most popular closed bridge, which is the Filipino-style, index-finger-pressing-down-upon-ring-finger closed bridge, with the thumb pressing against the side of the ring finger (it's basically "along for the ride" -- most of the clamping work is done by the index finger upon the ring finger). You'll notice most of the pros have now adopted this style closed bridge, with the "pure loop" style closed bridge (as taught in Mosconi's little red book) being quite rarely seen in pros these days.
Another closed bridge that is extremely stable is the Willie Hoppe style closed bridge, as shown here:
http://youtube.com/watch?v=sc4iaJWu8Ak#t=155s
(This link will jump you into the section where Willie demonstrates his closed loop bridge.)
I don't agree with Willie's stroke style (i.e. from the shoulder as shown in the video), but I've found his closed bridge to be extremely stable and rock steady. The only change I make, is not to let the flesh of my fingers "drag" on the shaft like he shows in the video. A little corn starch applied in there on the contacts points where the cue contacts my fingers fixes that nicely.
Another closed bridge that seems to work well -- albeit it would make you think it's completely against what's traditionally taught -- is the closed bridge that Earl Strickland uses. Basically, it's a traditional closed loop bridge (like taught in Mosconi's little red book), but Earl hooks his index finger on the OUTSIDE of his thumb, not on top of or on the inside of the thumb. Earl basically uses the top surface of his thumb as a "channel" to ride the cue shaft on top of; the ring finger provides the "left wall" and the index finger provides the "right wall" to guide the cue and keep it on track.
I also agree with the synopsis about a variation of the open bridge where the thumb, instead of sticking up in the air at a 45-degree angle (of course clamped against the index finger), the thumb is instead folded over onto the index finger. The cue travels between the knuckle of the index finger and the knuckle of the thumb, keeping the skin taught and preventing the flesh from moving to and fro. This gives added stability. Shane Van Boening uses this variation of the open bridge all the time, as do most Filipino pros.
Hope this is helpful,
-Sean